A
synaptosome is an isolated synaptic terminal from a
neuron. Synaptosomes are obtained by mild
homogenization of nervous tissue under isotonic conditions and subsequent fractionation using differential and density gradient
centrifugation. Liquid shear detaches the nerve terminals from the
axon and the plasma membrane surrounding the nerve terminal particle reseals. Synaptosomes are osmotically sensitive, contain numerous small clear
synaptic vesicles, sometimes larger dense-core vesicles and frequently one or more small
mitochondria. They carry the morphological features and most of the chemical properties of the original nerve terminal. Synaptosomes isolated from mammalian brain often retain a piece of the attached postsynaptic membrane, facing the active zone.